A 4.0-kg block slides along a frictionless surface with a constant speed of 5.0 m/s as shown. Two seconds after it begins sliding, a horizontal, time-dependent force is applied to the mass. The force is removed eight seconds later. The graph shows how the force on the block varies with time.









 16. What is the magnitude of the total impulse of the force acting on the block?
(a) 20 N  s (c) 48 N  s (e) 60 N  s
(b) 42 N  s (d) 54 N  s